1. Field of the Invention
This invention relates in general to techniques for avoiding both heat-seeking and radar missiles in a military aircraft, and particularly to a decoy towed behind the aircraft to attract the missile away from the aircraft.
2. Description of the Prior Art
Military aircraft are vulnerable to attacks from missiles. Extensive measures are available for evading radar detection. These measures include special coatings on the aircraft's skin, special shapes to the airframe, and electronic countermeasures. Also, metallic chaff can be ejected to create a false radar signal.
Heat-seeking missiles, on the other hand, are not confused by these radar countermeasures. A heat-seeking missile hones in on infrared radiation emitted from the exhaust plume of the jet engine. A jet fighter airplane may be able to evade a heat-seeking missile if provided with adequate warning, mainly by making extreme flight maneuvers. If the pilot or the radar detection system of the aircraft fails to detect a heat-seeking missile, a strike is likely. One proposed technique to counter heat seeking missiles would be to deploy a flare which burns or creates hot metal vapors. The flare might draw away the missile. However, the aircraft will quickly be out of range of the flare, and therefore, would soon be vulnerable again to another strike. Consequently, the proposals concerning pyrotechnic flares and chaff require detection of the heat-seeking missile before the chaff is deployed.
Targets have been towed behind the aircraft for practice firing of ground weapons. Also, U.S. Pat. No. 4,233,605 discloses towing a helicopter radar decoy behind the helicopter. The decoy has a radar cross-section that simulates helicopter blades. The decoy reflects a stronger radar signal than the actual helicopter, leading hostile weapons to the decoy. This decoy, however, has no effect on infrared-guided missiles.